In the inner side at the face plate of the color cathode-ray tube, three color phosphor patterns are arranged and so form the phosphor screen.
As the method these phosphors are spread to form a designated pattern in the inner side of the face plate, it is done slurry spread method by using photoresist blended with the phosphor and dry method by sensitizer with diazonium salt, diazonium salt is resolved to be exposed to mercury excited ultraviolet and then have adhesion in that ZnCl.sub.2 absorbs the moisture in the air.
The method of manufacturing the sensitizer by using these methods is disclosed Korean Patent 83-3421, filed July 25, 1983 and Korean Patent Application No. 83-3645, filed Aug. 4, 1983, etc.
As the former slurry spread method develops by washing unexposed part after spreading the phosphor slurry to the inner side of the face plate and exposing the only designated part through the shadow mask, there is an disadvantage that the exposure time is long because the photosensitivity is low and that it is unable to obtain the minute and phosphor pattern because exposed ultraviolet causes light scattering on the surface of the phosphor.
As the latter dry method is to spread the sensitizer in the inner side of the face plate and dry, then adhere by exposing and scattering the phosphor, where in wash phosphor remaining in unexposing area by blowing air and to form by destroying the tack which reveal the exposed sensitizer through dose of roading materials, it is able to obtain the good phosphor pattern than the predescribed slurry spread method, but it is difficult to remove the phosphor remaining to unexposed area clearly on account of removing by blowing air, there occurs color-remaining at the next time to spread the fluorescent film.
The clearness of the picture at the color cathode-ray tube is influenced by how fine, straight, right trio color phosphor patterns of red, blue, green can be formed.